Amazing Ash Cloud Spied from Space Station

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Clear skies and a passing space station combined for an
extraordinary view of Alaska's erupting Pavlof volcano on May 18.

An astronaut aboard the International Space Station snapped a
photo of ash streaming from the fiery peak in the Aleutian
Islands, about 625 miles (1,000 kilometers) southwest of
Anchorage.

Before Mount Pavlof started erupting on May 13, the volcano was as
snowy white as its twin, Pavlof Sister, seen sitting directly
northeast of the active volcano in the astronaut picture. The
combination of melting ice and snow, volcanic gases and lava has
sent
pyroclastic flows racing down Pavlof's slopes, seen in
earlier satellite images tracking the eruption. Pyroclastic flows
are lethally hot, superfast flows of gas and rock fragments.

Satellites and earthquake monitors help scientists at the
Alaska Volcano Observatory (AVO) track the ongoing eruption
at Pavlof and the more than 30 active volcanoes in Alaska, many
of which are far from towns, but can threaten planes with their
ash. America's biggest state relies on small planes to ferry
people and supplies to remote villages, and international cargo
travels from Anchorage to Asia. When clouds hide the ash cloud,
satellite heat imagery and seismic tremors help researchers
confirm volcanoes such as Pavlof are still actively erupting.
Local pilots also call in reports of ash and gas plumes to AVO
scientists.

Pavlof's ash column has reached as high as 22,000 feet (7,000
meters), forcing regional airlines to occasionally delay or
cancel flights to local villages and towns. Ashfall has been
reported in nearby communities, including Sand Point, Nelson
Lagoon, King Cove and Cold Bay, according to the AVO.

Scientists are also monitoring an ongoing eruption at Cleveland
volcano farther to the west in the Aleutian Islands. With no
seismic network at the remote site, scientists rely on satellites
and infrasound — low-frequency sounds created below the range of
human hearing — for
eruption monitoring at Cleveland volcano.